Stuck in Paris... rear brake binding... Help!

[Irlanski]

Hi All,
Apologies as did not do too much trolling for the answer to this one. Had a BMW dealer fit a new rear brake disk and pads on my 05 R1200GS last week. It seemed okay on riding although it was slightly binding and I put this down to pads bedding in - did about 200 miles without any noticeable problem.

My mate now riding it to Bucharest and I hope to pick it up next Sunday to head east. He rolled off the ferry today in Cherbourg but about half way to Paris he noticed the rear brake was beginning to bind. He said that when you apply the brakes hard when riding that the fast flashing ABS light and red warning triangle illuminate and then the pads seemed to release. Within 20 miles from Paris the rear brakes just bound too much and leaving it cool etc and then bleeding off a small quantity of fluid at the rear nipple the wheel freed up but unfortunately the problem has reoccurred. The front brake is working perfectly.

The BMW dealer did tell me last week that the pedal switch was not working consistently and would need replacement but said they did not have the part in stock and I could come back at a later stage - I'm not sure if this is related.

I thought maybe it might have been an excess of brake fluid might be the issue because the ABS unit was topped up some time prior to the new pads and disk being installed. Also I recall changing brake pads previously and the pistons did push in by hand with ease leading me to dismiss the possibility of the pistons seizing.

I'm at a loss! Any ideas what the problem could be? Any help appreciated - except any mention of a faulty ABS unit

 

[haditlowered]

possibly it's a stiff brake pedal pivot, maybe it slightly out of line making it stick "on", has it had a knock, bike fallen over on the pedal..., also the pin through the pads might have seized but if you've had new pads i doubt its that.

 

[Myke Rocks]

Much more likely to be the pedal sticking down slightly, trapping a column of brake fluid in the pipework. This is normally free to vent back to the master cylinder reservoir, and when trapped, expands when the brake rubs a little, thus increasing the braking it is exerting, thus heating the fluid more etc.
Step 1. Pull up brake pedal with hand and see does that relieve the problem.
If it does, free brake pivot.
If it does not, release brake fluid pressure from slave cylinder by opening bleed nipple and closing it again. This will at least get you moving without rear brake binding. Try not to use the rear brake and carry on. The brakes are linked, so it may come on sooner or later. A handy spanner to re-release the pressure via nipple may be advisable.
Myke

 

[Irlanski]

thanks... ive forwarded the advice so far... keep it coming!!

 

[Irlanski]

He has reverted to me saying that the brake pedal action is quite positive and topping out quite positively so we're still in a jam (pardon the pun)

Some postings indicating that the rear brake hoses are liable to internal collapsing and blocking passibly causing one way action of the fluid towards the cylinder but impeding its return?

 

[Bendy toy]

Take the caliper off the swing arm and put some plywood between the pads. Tie it securely with zip cable ties.
You won't have a back brake but it does very little in a full on emergency stop so nothing to lose sleep over.

 

[The Grey One]

Either you have a collapsed brake hose preventing the fluid returning or there is not enough free play in the pedal. I had a BMW dealer adjust the free play out when the worked on my rear brakes. The free play is there to allow for expansion due to heat. If there is little or no free play then the brakes wil bind as things warm up and get progressively worse until the wheel can hardly turn.


John

 

[oldnfat]

Either you have a collapsed brake hose preventing the fluid returning or there is not enough free play in the pedal. I had a BMW dealer adjust the free play out when the worked on my rear brakes. The free play is there to allow for expansion due to heat. If there is little or no free play then the brakes wil bind as things warm up and get progressively worse until the wheel can hardly

John

This is a good call, I have had the same symptoms. Increase the free play by undoing the lock nut at the bottom of the rear brake master cylinder and turning the shaft a couple of turns the re tighten the lock nut.

Cheers

 

[Irlanski]

This is a good call, I have had the same symptoms. Increase the free play by undoing the lock nut at the bottom of the rear brake master cylinder and turning the shaft a couple of turns the re tighten the lock nut.

Cheers

Thanks Guys and have passed that on - it seems like a very good synopsis of the possible problem to me. My worry is that it may have then lead to the ABS pump overworking and possibly damaging that - dread the thought! Its on a bench in BMW Paris now. They are saying something like front lever switch gone which triggers ABS and the system has run hot.... They won't know if the ABS is shot until they reset and do full diagnosis - whatever all that means. I'll keep you posted...

 

[SteveM]

Ahhhh...oui oui oui. Bon chance!!!

 

[Irlanski]

Okay... it's the worst news. A one month's tight schedule venture around the Black sea is looking very doubtful now. So the BMW dealership said the ABS unit needs replacement as well as the rear pads and possibly the rear caliper - disk okay. (Front brake switch okay?!) Excluding the caliper its all coming in at a tasty €2,800 - thats a lot of dosh to pour into a ten year old bike. Anyway, the item is not in stock and it will take a week to get it from Germany! My friend asked them to disable the ABS and give him the bike back - they initially refused saying it would be too dangerous but then on account of them not actually performing any work other than testing they capitulated and released the bike. It's a disaster after 6 months planning, visas etc and was to pick up a pillion who was to fly into Tiblisi.

Maybe the next few hours will bring some more clarity but as I see it now there are three options - Go forward without ABS or Servo or rear brakes, stay in Paris and consider the position or go back towards Cherbourg. We've decided going forward is not a sensible option but rather than go back to Cherbourg today were going to hold tough for a while in Paris and perhaps try to link in with some local BMW club or something and maybe try to source a second hand unit or something - I don't know!

There's a possibility too that the bike insurance will cover getting the bike home... were working on that too. It's a mess...

Does anybody have some friendly contacts in Paris that may be able to shed some light whilst the bike is still there... Were going to hold tough in Paris for the next 24 hrs anyway. Will update on progress if any...

 

[Rocketman]

Nothing really constructive to say really ,but my heart goes out to you fella there's nothing worse than planning a trip +expense and something like this happens .
Hope you get something worked out .......gav

 

[JerseyNeil]

How about getting in touch with the dealer that f*cked it up, I mean replaced the disc and pads last week. And see what they will do. They 'repaired' your bike and the repair has failed. Their workmanship should have some guarantee.

Neil

 

[The Grey One]

Okay... it's the worst news. A one month's tight schedule venture around the Black sea is looking very doubtful now. So the BMW dealership said the ABS unit needs replacement as well as the rear pads and possibly the rear caliper - disk okay. (Front brake switch okay?!) Excluding the caliper its all coming in at a tasty €2,800 - thats a lot of dosh to pour into a ten year old bike. Anyway, the item is not in stock and it will take a week to get it from Germany! My friend asked them to disable the ABS and give him the bike back - they initially refused saying it would be too dangerous but then on account of them not actually performing any work other than testing they capitulated and released the bike. It's a disaster after 6 months planning, visas etc and was to pick up a pillion who was to fly into Tiblisi.

Maybe the next few hours will bring some more clarity but as I see it now there are three options - Go forward without ABS or Servo or rear brakes, stay in Paris and consider the position or go back towards Cherbourg. We've decided going forward is not a sensible option but rather than go back to Cherbourg today were going to hold tough for a while in Paris and perhaps try to link in with some local BMW club or something and maybe try to source a second hand unit or something - I don't know!

There's a possibility too that the bike insurance will cover getting the bike home... were working on that too. It's a mess...

Does anybody have some friendly contacts in Paris that may be able to shed some light whilst the bike is still there... Were going to hold tough in Paris for the next 24 hrs anyway. Will update on progress if any...

Really? I expect all new parts will fix it but maybe in the same way as buying a new car fixes the problem of the ash tray being full. As to the ABS causing the symptoms first described I have my doubts. Checking the free play at the pedal takes minutes, the pedal should move freely before the push rod moves the piston in the rear brake master cylinder. I repeat if there is little or no free play the brake will begin to bind as the system heats up. This is nothing to do with the ABS at all. If it is a hose causing the problem then you might expect the seized rear brake to be released if you crack open the bleed screw on the caliper.

John

 

[Bendy toy]

Taking off the caliper will allow the bike to be used.

 

[fringe]

would suggest you look at the rear caliper and ensure the brake pad slider has been put back in appropriately. There is a metal backing plate that the pad mount should sit on. Item 6 http://www.rainbowbmw.com/BMWETK/Products/0307_34_10200.html

If the brake pad has been put on the wrong side of this slider/support bracket, it stops the pad from moving back and it will bind one pad up against the disc, with the heat I imagine the other side/pad could as well... worth a check

 

[roamer]

Before you bin the trip, the idea that the rear calipers is sticking,or more likely the brake pedal free play, they may have adjusted it to push the switch back,
My previous bike had a similar issue,
First try moving the rear wheel on the mainstand and operate the rear brake,
If it locks the wheel in the first 10 mm it may be worth adjusting for more free play, as when it heats up the slack disappears,
Also grab the caliper and roll it in its mountings, this should cause excess travel on the pedal, provided it's adjusted with enough free play, proving its not seized,
If it doesn't it may be freed off by undoing and forcing the piston back and pumping up again,
The abs would show a warning if it was at fault,,so provided it's got the servo action the fault is possibly less serious,
Good luck with a local fix, apologies for explaining so much,
Like others I feel it's worth a simple approach,,

 

[roamer]

It's a long shot, but if you are really stuck, and it's only the rear brake binding, everything ok, no warning lights,
I am currently heading north in France to a first overnight near Grenoble Wednesday and Langres or somewhere in that area on Thursday,
And would take a look ! Diagnose it for you ,possibly fix, once at my overnight,
This may or may not be any help, it's my trade so no guessing ,
I am on a tight schedule, but have time for a fellow biker,,
If we are to meet, I would prefer to talk through the problem live beforehand,
Pm me by 0930 cet, and I will give you my mobile number, as I will be driving until 15/1600 Wednesday
Cheers Roamer

 

[Irlanski]

Really appreciate all the feedback and have passed all on to my mate. Thanks Roamer for the offer to meet. Im very sure now that the pedal adjustment was not correct and caused the initial small rubbing then heat build up then more severe rubbing and accompanying heat buildup and that heat got transferred to the abs unit. The metal backing on the pads were warped apparantly. Fast flashing abs light and red warning triangle. Apparently the brake fluid looked loke shit too when he bled some off so i possibly think the abs is in trouble. Posted on bmw group france face book... not sure if any contact was made with my mate... looks like he is considering returning to Cherbourg. Its hard to control it from a distance....

 

[Bendy toy]

It's simply not tenable that heat from the brake could affect the ABS unit.
I suspect the dealer is simply quoting a price to replace anything that might be to blame.
Brake lever free play is easy to check and the pad fitting isn't difficult.
The most likely cause on a 10 years old bike is crudded up piston seals in the caliper. The easiest fix is a new caliper.